1. Field of the Invention
The present invention relates to rocket-launched spacecraft and, in particular, relates to boom assemblies that deploy extendable components of the spacecraft.
2. Description of the Related Art
Rocket-launched spacecraft, which include orbiting satellites and deep space probes, perform increasingly complex tasks. In particular, telecommunication satellites enable vast amounts of information, including voice and data, to be sent and received around the globe. In other examples, satellites equipped with earth imaging devices enable weather forecasters to more accurately study and predict global weather patterns. Furthermore, since satellites are positioned outside of the earth""s atmosphere, they provide an ideal platform for observing and studying the universe. Additionally, deep space probes equipped with increasingly advanced scientific instrumentation that are launched into a non-earthbound trajectory enable scientists to obtain heretofore unobtainable data about the solar system.
The rocket-launched spacecraft is launched into a preferred trajectory by rocket-propelled means that includes positioning the spacecraft into a relatively small capsule of a rocket-propelled vehicle. Thus, the typical spacecraft is required to be configurable between a storage configuration that enables the spacecraft to be positioned within the capsule of the rocket-propelled vehicle and a deployed configuration that enables the spacecraft to function in a desired manner while in outer space.
Thus, subsequent to the launching of the spacecraft, the spacecraft is typically configured for use by deploying an assembly of extendable components. For example, the assembly of extendable components may comprise an extended solar panel array that is used to convert collected solar radiation into electrical energy. In another example, the assembly of extendable components may comprise an extendable antenna assembly that is used to transmit and receive electromagnetic signals to and from a plurality of earth-based installations.
To deploy each assembly of extendable components, the typical spacecraft often utilizes a boom assembly. In particular, the assembly of extendable components is usually mounted to the extendable boom assembly which is adapted to fold-up in the storage configuration and fold-out in the deployed configuration. Furthermore, the boom assembly also serves as a support structure for supporting the assembly of extendable components while the boom assembly is in the deployed configuration. Moreover, although the spacecraft is often in a weightless environment, forces applied by rocket thrusters of the spacecraft that are sometimes used to correct the trajectory of the spacecraft may create considerable stress throughout the boom assembly. Therefore the boom assembly is required to be rigid and have sufficient structural integrity while in the deployed configuration.
As increasingly advanced types of spacecraft are being developed, it has become apparent that known types of boom assemblies provide insufficient capabilities. In particular, deep space probes currently being designed require boom assemblies that are capable of extending to unprecedentedly large sizes. Furthermore, the required boom assembly must be lightweight so as to reduce the amount of fuel that is needed to launch the spacecraft into the required trajectory, be reducible to a small size so as to enable the large boom assembly to fit into the small capsule, and have a high degree of strength when fully deployed. Moreover, since cost is a major consideration in the design of spacecraft, it is preferable for the boom assembly to have a simple design so as to reduce the manufacturing costs of the boom assembly.
Hence, there is a continuing need for extendable boom assemblies for spacecraft that are lightweight and are readily foldable into a compacted storage configuration for launch of the spacecraft. The boom assembly should also be readily deployable into an extended configuration upon the spacecraft reaching a desired trajectory and have sufficient strength to maintain spacecraft components in a desired deployed configuration.
The aforementioned needs are satisfied by the spacecraft boom assembly of the present invention comprised of an elongate boom having at least one opening formed at a location along the boom. In particular, the at least one opening defines at least one folding region so as to permit the elongate boom to be folded about the at least one folding region to thereby reduce the length of the elongate boom. Furthermore, the elongate boom is formed of a resilient material so as to store elastic energy when the elongate boom is in the folded configuration to thereby bias the folded elongate boom into an unfolded deployed state.
In another aspect of the invention, the aforementioned needs are satisfied by the spacecraft boom assembly of the present invention having a storage and a deployed configuration. In particular, the assembly comprises a first and a second mounting member and a foldable interconnection connected between the first and the second mounting members. Furthermore, the foldable interconnection is formed of an elastic material that is biased into a deployed configuration wherein the first and second mounting members are maintained in a deployed configuration such that the foldable interconnection rigidly maintains the first and second mounting members in a desired orientation with respect to each other such that the length of the boom assembly is a deployed length. Moreover, the foldable interconnection is adapted to permit release from the deployed configuration so that the first and second mounting members can be positioned in a storage configuration wherein the first and second mounting members are positioned so as to reduce the length of the boom assembly.
In another aspect of the invention, the aforementioned needs are satisfied by the elongate structural support member for a spacecraft comprising a first rigid member having a first and a second end, a second rigid member having a first and a second end, and a foldable connecting member integrally attached to the first ends of the first and second rigid members so as to interconnect the first and second rigid members. In particular, the foldable connecting member is bendable so as to allow the first and second rigid members to be positioned substantially adjacent each other substantially along the lengths of the first and second rigid members in a storage configuration. Moreover, the foldable connecting member is biased towards a deployed configuration wherein the first rigid member is rotated about the connecting member with respect to the second rigid member so that the first and second rigid members extend outward from the foldable connecting member.
In another aspect of the invention, the aforementioned needs are satisfied by the boom assembly for a spacecraft comprising a first boom sub-assembly having a first and a second rigid section with a folding section interposed therebetween. In particular, the folding section enables the first and second rigid sections to be folded about the folding section to thereby reduce the length of the first boom sub-assembly in a storage configuration. Furthermore, the folding section is biased so as to urge the first boom sub-assembly into a deployed configuration. The boom assembly further comprises a second boom sub-assembly having a first rigid section and a folding section wherein the second boom sub-assembly is mounted to the second rigid section of the first boom sub-assembly. Moreover, the folding section of the second boom sub-assembly enables the first rigid section of the second boom sub-assembly to be folded with respect to the second rigid section of the first boom sub-assembly to reduce the length of the second boom sub-assembly with respect to the first boom sub-assembly.
In another aspect of the invention, the aforementioned needs are satisfied by the structural support member for a spacecraft boom assembly, the support member comprising a plurality of rigid sections that include a first, a second, and a third rigid section and a plurality of foldable sections that interconnect the plurality of rigid sections. In particular, the plurality of foldable sections include a first foldable section that interconnects the first and second rigid sections and a second foldable section that interconnects the second and third rigid sections. Furthermore, each of the foldable sections is formed of a resilient material having a shape that is biased into a rigid unfolded state such that the foldable sections rigidly interconnect the rigid sections so as to maintain the structural support member in a rigid deployed configuration. Moreover, each of the foldable sections is configurable into a strained folded state so as to enable the plurality of rigid members to be positioned substantially adjacent each other substantially along the lengths of the plurality of rigid members so as to place the structural support member in a storage configuration having a reduced size. Additionally, the first and second rigid sections are able to fold and unfold with respect to each other along a first plane and the second and third rigid sections are able to fold and unfold with respect to each other along a second plane such that the first and second planes intersect each other.
The spacecraft boom assembly of the present invention is formed from an improved structural element that is both bendable and compressible so as to enable the boom assembly to be easily folded into a storage configuration so that the boom assembly can be stowed within the relatively small payload space of a launching vehicle. Furthermore, since the foldable sections of the structural element are formed of a resilient material, the elastic energy stored within each of the folded foldable sections provides each of the foldable sections with a bias that urges the boom assembly to self-extend from the storage configuration to the deployed configuration. Moreover, the structural element, when in the deployed configuration, provide sufficient rigidity so that the boom assembly is capable of supporting extending components of the spacecraft. Additionally, the extendable structural element is relatively inexpensive to manufacture, is lightweight, and is capable of extending into relatively large sizes. These and other objects and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.